Hammer-drill.



A. I. CARTER.

HAMMER DRLL. APPLICATION FILED Nov. 2o, 1911. RBNEWED JAN. 4, 191s.

A. J. CARTER.

HAMMER DRLL. APPLICATION FILED 110mm), 1911. nHNBwBD 111114, 1913.

1,069,853, Patented Aug. 12, 1913.

2 SHEETS-SHEET 2.

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ANDREW J'. GAMER, OF VICTOR, COLGByADO.

'HAMMER-:DRILL Application filed November 20, 1911, Serial No. 661,288.

To all whom, it may concern:

Be it known that I, ANDREW J. CARTER, a citizen of the United States,` residing at Victor, county of Teller, and State of Colorado, 'have invented certain new and useful Improvements in Hammer-Drills; and I, do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in y the art to `which it appertains t0 make and use the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

My invention relates to improvements in hammer drills adapted to be operated either by hand or other suitable power. As illustrated, in the drawing, it is assumed that the machine is operated by hand, but it is evident that the crank shaft may be rotated by an electric motor or other power. T he device is, however, thoroughly practicable as a hand rock drill, and, for this purpose, the drill-steel 'is supported in a chuck arranged to be rotated as the crank shaft is operated, the said shaft carrying a sprocket wheel which is connected by means of a chain with a short shaft journaled in the casing and having a gear connection with the drill-stecl-carrying chuck.

Mounted to reciprocate within the casing in alinmnent with the drill-steel is a hammer with which is pivotally connected a stem serving as a sort of pitman, whose rear extremity is equipped with an offset head forming a shoulder against which the cranks of the shaft are adapted to engage as the shaft is rotated.l Surrounding the stem and between the hammer and a stop mounted on the casing is interposed a power spring, which is of the helical type and arranged to be compressed as the hammer is moved rearwardly by the action of a crank upon the head of the pitman. As the rotation of the shaft is continued, after the hammer reaches its rearward limit of movement, the pitman is released from its engaging crank, and the recoil of the spring drives the hammer forward, after which the pitman head is caught by the next crank and the operation is repeated.

As illustrated in the drawing, the crank shaft is equipped with three U-shaped cranks', the closed outer end of each crank serving to engage the head of the hammer pit-man, and, after the hammer has reached Specification of Letters Patent.

Patent-ed Aug., 12,1913.

its rearward limit of movement, one of the cranks acts on the pitman forward of its head to facilitate the quick release of the hammer by the almost instant disengagement of the engaging crank from the head of the pitman.

In order to produce a steady, even rotation of the crank and prevent a relatively quick movement, immediately after the hammer is released, a leaf spring is employed, the said spring being engaged by one of the cranks of the shaft, the said spring serving to advantageously interpose the necessary resistance to prevent a sudden jump of the crank shaft, which would result in a sort of jerk when the crank should next strike the head of the pitman, which would be injurious to the mechanism and also annoying to the person operating the machine. However, by the employment of the said spring, ya substantially even rotary action of lthe crank shaft is obtained.

Having briefly outlined myv improved construct-ion, I will proceed to describe the same in detail, reference being made to the accompanying drawing, in which is illustrated an embodiment thereof.

In this drawing: Figure l is a top plan view of the drill mechanism, the casing being shown in horizontal section, the rear part of the guide shell being broken away. Fig. 2 is a side elevation ofthe same, the crank shaft beingsectionized by cutting the same through the cranks and the casing being sectionized and partly broken away on one side to illustrate an openingv through which the cranks of the shaft successively protrude to engagement with a spring as the shaft is rotated. In this View, the detachable side plate of the casing is removed. Fig. 3 is a side elevation of the complete drill shown on a smaller scale, with the guide shell shown in central longitudinal section. Fig. 4 is a transverse section, taken through the casing ust forward of the hammer, being a Section taken on the line 4-4 of Fig. l, looking toward the left. Fig. 5 is a top plan view of the rear portion of the guide shell shown on a larger scale than in Fig. 3.

The same reference characters indicate the same parts in all the Views.

Let the numeral 5 designate the casing'of the drill, the body portion 6 being U- shaped,-see Fig. 1:,-the casing chamber 7 being closed on one side by a plate 8 se- Renewed January 4, 1913. Serial No. 740,236.l

cured by means of bolts 9. this plate, access may be gained to the interior of the mechanism which may be readily removed. The lower' part of the casing' is provided with longitudinal flanges yl() adapted to engage grooves 12 formed in instrumentality of a feed screw 15 threaded.

in a hollow, internally-threaded bolt 16 earried by a depending sleeve 17 formed integral with the bottom of the casing, as illustrated in Fig. 4.4 The exterior of the bolt 1G and the interior of the sleeve 17 are smooth. They are held in operative relation withv each other by means of the bolt head bearing' against one end of the sleeve and a nut threaded upon the bolt and bearing against the other end of the sleeve.

"The rear extremity of the feed screw is journaled-in a cross piece 18 carried by rods 19 connected with the guide shell 13, and, therefore, relatively stationary. To the rear end of the feed screw is connected a hand crank 20 adapted to'engage the cross piece 18, when the feed screw is at its forward limit of movement. lnterposed between a shoulder at the rear extremity of the threadcd portion of the feed screw and the cross piece 18 is a helical spring 22. By the employment of thisl spring, itbecomes practiL cable to operate the feed screw intermittently,-that is to say, when the drillssteel 23 is against the rock, the casing, and therefore the steel, may be subjected to 'spring pressure by turning the feed screw in the direction, which, under other circumstances, would cause the casing to move forwardly. However, asthe casing cannot move forwardly, and, as the feed screw cannot move forwardly, it will back out of the nut, so to speak, and compress the spring 22 between the cross piece 18 and the shoulder 21. ln this way, the casing may be placed under any desired pressure and this pressure `utilized until the drill-steel has entered the rock far enough to exhaust the pressure, so to speak, when the feed screw may be given another series of turns with the same result as before.

The drill-steel 22 is inserted in a chuck 24, journaled in an end plate 25 of the casing, and a. partition 26 formed integral with the ttl-shaped body member of the casing. rlhe drill-steel is provided with a lug 27, which enters a slotl 28 formed in the forward ex* tremity of the chuck, whereby the steel is caused to rotate with the chuck. The rotary movement is imparted to the chuck by virtue of a gear 29, which is fast on the chuck and meshes with a pinion 30 fast on a short shaft By removing l 31 journaled in one side of the casing and carrying a sprocket wheel 32 connected by means of a chain 33 with -a second sprocket 34 fast on the crank shaft 35, the latter being journaled iu the casing, as shown at 36, and provided with a plurality of cranks 37. As shown in the drawing', there are three of these cranks equi-distantly spaced on the shaft and adapted to engage the T-hea'd 38 of a sort of pitman or swinging stem 39 pivoted at 40 on the reduced rearward projection 41 of the hammer 42, which is polygonal in shape, preferably hexagonal and vertically elongated in cross section, the apices 43 formed by one pair of upperand one pair of lower'sides engaging V-shaped grooves 44 formed in upper and lowerguide blocks 45 secured to the top and bottom walls of the casing by bolts 46.

The pitman 39 is normally held in alinement with the longitudinal axis of the hammer by a pair of leaf-springs 47 secured to the reduced part 41 of the hammer by means of screws 48 or other suitable fastening devices, the rear extremities of the springs embracing the pitman on opposite sides and reinforced circumferentially, as shown at 49, 'whereby the pitman is embraced by the f springs in such a manner as to maintain its aforesaid alinernent with the axis of the hammer. lnterposed between the rear extremity of the hammer and a cross partition located in the casing and composed of members 50 and 51, formed on the body of the casing and the plate 8, respectively, is a power spring 52 of the helical variety.

From the foregoing description, the use and operation o-f my improved rock drill will be readily understood. Assuming that the guide shell is suitably supported in roximity to the rock to be drilled, where y it isheld relatively stationary, the casing may be fed toward the rock by the use of a feed screw in the usual manner, or intermittently by the employment of the special construction heretofore explained. If it is desired to operate the machine by hand, a crank 53 vwill be applied to one of the protruding squared extremities 54 of the crank shaft.

The crank shaft will then be rotated, and,

during such rotation, a rotary movelnent will be imparted to the chuck and drill-steel by virtue of the connection and arrangement of parts heretofore described. Also, during suchV rotation, the cranks 37 of the shaft 35 will successively engage the T- head 38 of the 'hammer pitman 39 and impart rearward movement to the hammer, the latter being released after it has reached its limit of movement in the aforesaid direction. During each rearward movement of the hammer, the power spring is compressed andl placed under such tension that, when the hammer is released from the'connection of its pitman with a crank of the operatvis ing shaft, the recoil of the spring, acting on the hammer, will cause the latter' to strike the rear extremity of the drill-steel with a powerful blow.

The three cranksI of the operating shaft 35 are so arranged that, when one crank, acting upon the T-head of the pitman 3S), has drawn the hammer 42 to its rearward limit of movement, the crank immediately in the rear, considered with reference to the travel of the crank shaft, will be in engagement with the hammer stem forward of the head of the latter, and traveling in aii arc 55 of the dotted circle in Fig. Q will actto crown the pitman laterally, while the crank, engaging the head of the pitman, is traveling in an arc 5G of the same circle, whereby7 the pitman is moving in one direction, while its head-engaging crank is moving` in the opposite direction with the result that the pitman, together with the hammer, 'is instantly released as soon as the hammer reaches its rearward limit of movement. This is a very important feature of the construction. As the hammer moves forwardly, or to the dotted line position in Fig. 2, the T-head 38 of its pitman stops ljust in the rear of the next crank of the shaft, the said crank moving to engagement with the T-head practically immediately after the hammer stroke. It will thus be seen that no time is lost in releasing the hammer after it has reached the limit of its rearward stroke. or in beginning the rearward stroke after the hammer. has mparted its blow to the drill-steel. At the instant that the pitmanA is disengaged from one crank of the shaft, the crank immediately forward, considered with reference to the rotary travel of the crank shaft, will be in engagement with a leaf-spring 57, which is secured to the casing, as shown at 58, and is located just outside of an opening 5t) in the top of the casing, the said opening being of sutlicient size to allow the cranks 3T to pass therethrough as the crank shaft is ro tated. This spring, acting successively upon the cranks, during and immediately after the release of the hammer, prevents the crank shaft from jumping, so to speak,

at the instant of the hammers release and' before the next crank engages the T-head of its pitman. By virtue of this construction, it is practicable to impart to the crank shaft a steady even stroke, during the 'operationof the machine. lt will, of course, be practicable to apply a fly-wheel to the crank shaft, which will further aid in imparting a uniformly even rotary movement, and also, by virtue of its momentum, increase the ease with which the machine is operated. The partition 50 is provided with a vertically-disposed slot (l0, in which the pitman or swinging stem 39 oscillates during the operation of the drill. This slot. is of such width that the pitman p'actically fills the same., whereby the slot forms a vertical guide for the pitman during the operatlon of the machine.

The crank shaft is equipped with collars ($1, which are arranged to engage the inner extremities of the bea rings 3G. thus securing the shaft against longitudinal movement.

Having thus described my invention, what I claim is zl. In a rock drill, the combination with a casing, of a hammer mounted to reciprocate therein, a pitman pivoted to the hammer, a power spring interposed between the rear extremity of theI hammer and a stationary part of the casing, and a shaft journaled in the casing and having a plurality. of cranks whose path intersects the produced longitudinal axis of the hammer, the pitman having a stop which is successively engaged by each crank and released'by the crank following as the shaft rotates and yieldable means for holding said pitman in position to be actuated by the cranks, substantially as described.

2. In a rock drill, the combination with a casing, of a hammer mounted to reciprocate therein and spring actuated during its forward stroke, a shafty mounted to rotate in the casing and having a plurality of U-shaped cranks, a pitman pivoted to the hammer and equipped with a shoulder lying in the path of the cranks as the said shaft is rotated, the path of the cranks intersecting the produced longitudinal axis of the hammer, and

'yieldable means for holding said pitman in position to be actuated by the cranks, ,the arrangement beingsuch-that the cranks of the shaft successively engage and release the hammer pitman as the shaft is rotated, substantially as described.

3. A rock drill including a casing, a hammer mounted to reciprocate therein and spring-actuated during its forward stroke, the hammer being equipped with a pitman pivotally mounted thereon, yieldable means for holding said pitman normally in line with the axis of the hammer, a shaft journaled in the casing and having a plurality of cranks, thcpitman having a shoulder and the cranks of the shaftbeing arranged to successively engage and. release the said shoulder as the shaft is rotated, one of the cranks actin" on the pitman forward of the shoulder andlaiding. to disengage the engaging crank from the shoulder when the hammer is at its rearward limit of movement,

i substantially as described.

4. A rock drill including a casing, a spring actuated hammer mounted to reciprocate therein and having a rearwardly extending pitman pivotally mounted thereon and equipped with a shoulder, yieldable means for holding said pitman normally in line with the axis of the hammer, a shaftI jourvnaled in the casing and having a plurality of U-shaped cranks arranged to successively engage and straddle said shoulder as the shaft is rotated, the crank immediately in the rear ot the shoulder engaging crank, considered with reference to the direction of travel of the cranks, acting on the pit-man to aid in disengaging the shoulder of the latter from its engaging crank, when the hammer has reached its rearward limit of movement, substantially as described.

5. A rock drill including a casing, a hammer mounted to reciprocate therein, a pit-- man pivota'llyA connected with the hammer and. extending rearwardly therefrom, means for yieldingly holding said pitman in the direction of the length olf the hammer, a power spring interposed between the rear extremity of the hammer and a stationary part of the casing, a rotary shaft having a plurality of cranks arranged to successively engage and release the pitman as the shat't rotates, one of the cranks acting on the pitman in the rear ot another crank, considered with reference to the `travel of the cranks, to aid in disengaging the pitman from the forward crank, substantially as described.

G. In a rock drill, the combination with a easing and a drill-steel mounted therein, of a hammer mounted to reciprocate in the casing and having its axis in alinement with the axis of the drill-steel, a power spring interposed between the rear extremity ot the hammer' and a stationary part of the casing, a pitman pivoted to the hammer and extending rearwardly therefrom, .the Said pitman being surrounded by the power spring, yielding' means for normally holding said pitman in a line parallel to the axis ot the hammer, the stationary part of the casing engaged by the rear extremity of the power spring being slotted' to receive the pitman and allow the latter to oseillate, the rear extremity ot' the pitman having a shoulder,

a shaft journaled in the casing and having a plurality ot' cranksI adapted to successively engage and release the said shoulder, the crank in the rear of the shoulderfengaging crank, considered with reference to the travel ofthe said cranks, serving to impart a lateral thrust to the pitman when the hammer has reached its rearward limit of movement to facilitate the disengaging of the pitman-shoulder-engaging crank, substantially as described.

7. A rock drill including a casing,a spring actuated member mounted to reciprocate therein and equipped with a stem having a shoulder, a shaft journaled in the casing and having a plurality of cranks adapted to act successively on the shoulder of thestem as the shaft is rotated, the casing being equipped with a spring also lying in the path of the cranks and arranged to be acted on by one crank as another crank is disengaged roin the shoulder of the hammer stem, for the purpose set forth.

S. A rock drill including a casing,a spring actuated hammer mounted to reciprocate therein, the hammer beingequipped with a stem provided with a shoulder, a shaft journaled in the casing and equipped with a plurality of cranks, the shoulder of the stem lying in the path ot' the cranks, the casing having an opening in one of its walls and a spring located adjacent said opening and lying in the path of the cranks as the shaft is rotated, the spring being engaged by one crank as another crankbecomes disengaged t'rom the shoulder of the hammer stem, substantially as described.

ln testimony whereof I ailix my signature in presence ot' two Witnesses.

ANDREW J. CARTER.

vWitnesses C. D. GURNEY, XVM. I. Dukes. 

